The shadow of the man in black has followed fourteen-year-old Amy Cahill and her younger brother Dan on their worldwide search for 39 Clues that lead to a great power. The man has tried to kill them and he is a Madrigal, as were their parents. And now the man is ready to step out of the darkness for their final confrontation.

Xander Panda's plan to host a panda party falls through, since he is the only panda at the zoo, but when he extends the invitation to all of the bears, complications ensue. Includes author's note on the wonders of the animal kingdom and the international effort to save pandas from extinction.